Joint for artificial limbs



March 30, 1948. I sc w z F 2,438,581

JOINT FOR ARTIFICIAL LIMBS Filed Feb. 26, 1945 wu-wme v Patented Mar. 30, 1948 UNITED STATES- ENT- OFFICE 2338,5815 v 101m: roa afn'miciar; 'LIMBS Emil- Sehwarzkcpf, Los Angel'es'; Cant. Application. February 26, 1945;.SerialNor579.765

G-Ciaims. (01. 28 7 96) This invention relates to' a iointfor an artificial body member, andmore particularly to an ankl'e joint that connects an artificial root memberto' the lower. extremity of? an artificiall'gi Generally, ankle joints for this purpose are well-known- Itis one of the objects oi this' invention to improve in general-joints of this character.

it is another; objfeotof tmsinventicn toensure that the jointlwill remain adequately lubricated and freely movable, and without producing any annoying creaks.

In this way, dismantling of the. artificialmembers for relubrication is entirely obviated even after long: periods of. service. j

Thisinvention possesses. many other advantages, and has Other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose, there is'shown a form in the drawings accompanying and forming part of the present specification. The form will now be: described in detail, illustrating the general principles of the invention; but it is to' be understood that this detailed description is not to be taken in a limiting sense, since the scope'of this inventionis best defined by the appended claims.

Referring to the drawings 2 Q Figure 1 is a diagrammatic side elevation of an artificial foot and ankle member incorporating the invention; and

Fig. 2 is an enlarged sectional view, taken along plane 22 of Fig. 1, some of the elements being broken away to reduce the size of the figure.

There is indicated the lower end I of an artificial leg to which is jointed an artificial foot 2. The joint is so arranged that the foot 2 may be moved about an axis 3, corresponding in position to the ankle joint. Motion of the artificial foot 2 is restrained about the axis 3 by the aid of the structure illustrated most clearly in Fig. 2.

One element of the joint structure is a pin member 4 that has a cylindrical exterior surface. It is attached to the artificial leg I as by the aid of a pair of studs 5 and 6. These studs have axes transverse to the axis 3, and are spaced apart to provide a sufficiently rigid support for the member 4. The lower ends of these studs 5 and 6 may be threaded appropriately into the pin 4.

In order to provide a sufliciently large seat for holding the joint structure in position with respect to the artificial leg I, there are attached to the ends of the member 4 a pair of extensions 1 and 8. Although these members are shown as directed the sides of the hollow head 2 made (if separate pieces. telescoping over the (if pill 4'; Slfh a structure not essential.

Extensions 1, and, a are provided with appropriate througlij apertures 9" for the assage of the studs" Sand e. this. way, the members! and tj are retain d again t removal from: pm 411 The eaterier tsurraees of extensions T and fl; can rest upon appropriate Saddle suiffacs attached to the leg member I; f v

xterior" Cylindrical surface of member serves as the nner ball-race for two sets of balls in and; l l. These two sets of balls. are arranged symmetrically "aboutian axis l2? ofa fastening bolt l3; This bolt is. arranged to extend downwardljy into an aperture in the artificial foot 'z andto be fastened therein asby nut 3Q. Fastening" bolt I 3 has a hollow cylindrical, head I4 through. which the. member 4 extends. In the interior of the lieadth'ereis aninwardly' directed annular flange. [5; This flange serves to separate thetwofsets'oflbal'l's l'l'i'andl 'l andal so serves .to provide outer ballraees,

The balls Hlf'and Hare confined against appreciable. axialmoverrient by the. "inner surfaces [6 and" [Tot the members IIand 'B. Lubricant, such as grease or the like 'may'b'e packed around the balls 01 and l'!.. The pin. 4 is prevented from axial movement by the. engagement of balls Ill and l {with the flangeIIS'. Lubricant retaining rings [8. and [Q are. provided; having inwardly. flanges overlapping" respectively the flanges 20 and 2! formed at the inner ends of the members 1 and 8. These rings are press fitted over the cylindrical portions 22 and 23 at M. A sealing ring 24 of cork, or the like, is interposed between the ring I8 or l9 and the face of the extension 22 or 23. These rings 24 extend inwardly to overlap the flanges 20 and 2! and, therefore, confine the lubricant to the hollow head I 4.

Once the joint structure is packed with lubricant, there is no substantial loss of lubricant from the hollow head l4. Accordingly, the necessity of dismantling the joint for relubri-cating is obviated.

The inventor claims:

1. In a device of the character described: a pin member; extensions at each end of the pin member. each of said extensions having an outwardly facing annular shoulder adjacent the inner end of the extension; means for fastening said pin member to an artificial leg, including a pair of studs transverse to the axis of the pin; a bolt having a hollow head through which the pin member passes, said head having an intermediate flange, co-operating with the inner ends of said extensions and the pin to define a pair of ball races; balls in said races; and retaining rings carried respectively by the opposite sides of the head and having portions co-operating with said shoulderson the extensions for sealing the space in the head.

2. In a device of the character described: a pin member; extensions at each end of the pin member; means for fastening said pin member to an artificial leg, including a pair of studs transverse to the axis of the pin; a bolt having a hollow head through which the pin member passes, said head having an intermediate flange, co-operating with the inner ends of said extensions and the pin to define a pair of ball races; balls in said races; said extensions having exterior shoulders substantially co-planar with the opposite sides of the head; a sealing ringoverlapping the shoulder and the side of the head for each extension; and retaining rings attached respectively to opposite sides of'the head for holding said sealing ringsin place.

3. In a'device of the character described: a pin member; extensions at each end of the pin member, each of said extensions having a transverse aperture; means for fastening said pin member to an artificial leg, including a pair of studstransverseto the axis of the pin and passing respectively through said apertures in the extensions; a bolt having a hollow head through which the pin member passes, said head having an intermediate flange, co-operating with the inner having a hollow head through which the pin ends of said extensions and the exterior surface of the pin to define a pair of ball races, respectively on opposite sides of the flange; balls in said races; said extensions having shoulders sub stantially flush with the respective sides of the V retaining rings.

hollow head; a pair of retaining rings pressed onto the head and extending inwardly; and sealing rings extending over the shoulders and the sides of the hollow head, and held in sealing relationship by the retaining rings.

4. In a device of the character described: a pin member; extensions at each end of the pin member, said extensions respectively having outwardly facing annular shoulders adjacent their inner ends; means for fastening said pin member to, an artificial leg, including a pair of studs transverse to the axis of the pin member; a bolt member passes; means forming a radial and thrust bearing between said hollow head and said pin member; and retaining rings carried respectively by the opposite sides of the head, and having portions co-operating with said shoulders on the extensionsfor sealing the space in the head.

5. In a device of the character described: a pin. member; extensions at eachend of the pin member; means for fastening said pin member to an artificial leg, including a pair of studs transverse to the axis of the pin; a bolt having a hollow head through which the pin member passes; means forming a radial and thrust bearing between said hollow head and said pin member; said extensions respectively having exterior shoulders substantially coplanar with the opposite sides of the head; a sealing ring overlapping the shoulder and the side of the head for each extension; and retaining rings attached respectively to opposite sides ofthe head for holding said sealing rings in place.

6. In a device of the character described: a pin member; extensions at each endof the pin member; means for fastening said pin member to an' artificial leg, including a pair of studs transverse to the axisof the pin; a bolt having a hollow head through which the pin member passes; means forming a radial and thrustv bearing between said hollow head and said pin member; said extensions having shoulders substantially flush with the respective sides of said head; a pair of retaining rings, pressed onto the head and extending inwardly; and sealing rings extending over the shoulders and the sides of said head, and held in sealing relationship by the EMIL SCHWAR KOPF;

REFERENCES CITED The following references are of record in the file of this patent: I

UNITED STATES PATENTS V Date 

